[SCSI] sd/scsi_lib simplify sd_rw_intr and scsi_io_completion
This patch simplifies "good_bytes" computation in sd_rw_intr().
sd: "good_bytes" computation is always done in terms of the resolution
of the device's medium, since after that it is the number of good bytes
we pass around and other layers/contexts (as opposed ot sd) can translate
that to their own resolution (block layer:512). It also makes
scsi_io_completion() processing more straightforward, eliminating the
3rd argument to the function.
It also fixes a couple of bugs like not checking return value,
using "break" instead of "return;", etc.
I've been running with this patch for some time now on a
test (do-it-all) system.
Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 3d04a9f..4c4add5 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -855,8 +855,7 @@
* b) We can just use scsi_requeue_command() here. This would
* be used if we just wanted to retry, for example.
*/
-void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes,
- unsigned int block_bytes)
+void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
{
int result = cmd->result;
int this_count = cmd->bufflen;
@@ -921,87 +920,72 @@
* Next deal with any sectors which we were able to correctly
* handle.
*/
- if (good_bytes >= 0) {
- SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n",
+ if (good_bytes > 0) {
+ SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
+ "%d bytes done.\n",
req->nr_sectors, good_bytes));
SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg));
if (clear_errors)
req->errors = 0;
- /*
- * If multiple sectors are requested in one buffer, then
- * they will have been finished off by the first command.
- * If not, then we have a multi-buffer command.
- *
- * If block_bytes != 0, it means we had a medium error
- * of some sort, and that we want to mark some number of
- * sectors as not uptodate. Thus we want to inhibit
- * requeueing right here - we will requeue down below
- * when we handle the bad sectors.
- */
- /*
- * If the command completed without error, then either
- * finish off the rest of the command, or start a new one.
+ /* A number of bytes were successfully read. If there
+ * is leftovers and there is some kind of error
+ * (result != 0), retry the rest.
*/
- if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL)
+ if (scsi_end_request(cmd, 1, good_bytes, !!result) == NULL)
return;
}
- /*
- * Now, if we were good little boys and girls, Santa left us a request
- * sense buffer. We can extract information from this, so we
- * can choose a block to remap, etc.
+
+ /* good_bytes = 0, or (inclusive) there were leftovers and
+ * result = 0, so scsi_end_request couldn't retry.
*/
if (sense_valid && !sense_deferred) {
switch (sshdr.sense_key) {
case UNIT_ATTENTION:
if (cmd->device->removable) {
- /* detected disc change. set a bit
+ /* Detected disc change. Set a bit
* and quietly refuse further access.
*/
cmd->device->changed = 1;
- scsi_end_request(cmd, 0,
- this_count, 1);
+ scsi_end_request(cmd, 0, this_count, 1);
return;
} else {
- /*
- * Must have been a power glitch, or a
- * bus reset. Could not have been a
- * media change, so we just retry the
- * request and see what happens.
- */
+ /* Must have been a power glitch, or a
+ * bus reset. Could not have been a
+ * media change, so we just retry the
+ * request and see what happens.
+ */
scsi_requeue_command(q, cmd);
return;
}
break;
case ILLEGAL_REQUEST:
- /*
- * If we had an ILLEGAL REQUEST returned, then we may
- * have performed an unsupported command. The only
- * thing this should be would be a ten byte read where
- * only a six byte read was supported. Also, on a
- * system where READ CAPACITY failed, we may have read
- * past the end of the disk.
- */
+ /* If we had an ILLEGAL REQUEST returned, then
+ * we may have performed an unsupported
+ * command. The only thing this should be
+ * would be a ten byte read where only a six
+ * byte read was supported. Also, on a system
+ * where READ CAPACITY failed, we may have
+ * read past the end of the disk.
+ */
if ((cmd->device->use_10_for_rw &&
sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
(cmd->cmnd[0] == READ_10 ||
cmd->cmnd[0] == WRITE_10)) {
cmd->device->use_10_for_rw = 0;
- /*
- * This will cause a retry with a 6-byte
- * command.
+ /* This will cause a retry with a
+ * 6-byte command.
*/
scsi_requeue_command(q, cmd);
- result = 0;
+ return;
} else {
scsi_end_request(cmd, 0, this_count, 1);
return;
}
break;
case NOT_READY:
- /*
- * If the device is in the process of becoming
+ /* If the device is in the process of becoming
* ready, or has a temporary blockage, retry.
*/
if (sshdr.asc == 0x04) {
@@ -1021,7 +1005,7 @@
}
if (!(req->flags & REQ_QUIET)) {
scmd_printk(KERN_INFO, cmd,
- "Device not ready: ");
+ "Device not ready: ");
scsi_print_sense_hdr("", &sshdr);
}
scsi_end_request(cmd, 0, this_count, 1);
@@ -1029,21 +1013,21 @@
case VOLUME_OVERFLOW:
if (!(req->flags & REQ_QUIET)) {
scmd_printk(KERN_INFO, cmd,
- "Volume overflow, CDB: ");
+ "Volume overflow, CDB: ");
__scsi_print_command(cmd->data_cmnd);
scsi_print_sense("", cmd);
}
- scsi_end_request(cmd, 0, block_bytes, 1);
+ /* See SSC3rXX or current. */
+ scsi_end_request(cmd, 0, this_count, 1);
return;
default:
break;
}
- } /* driver byte != 0 */
+ }
if (host_byte(result) == DID_RESET) {
- /*
- * Third party bus reset or reset for error
- * recovery reasons. Just retry the request
- * and see what happens.
+ /* Third party bus reset or reset for error recovery
+ * reasons. Just retry the request and see what
+ * happens.
*/
scsi_requeue_command(q, cmd);
return;
@@ -1051,21 +1035,13 @@
if (result) {
if (!(req->flags & REQ_QUIET)) {
scmd_printk(KERN_INFO, cmd,
- "SCSI error: return code = 0x%x\n", result);
-
+ "SCSI error: return code = 0x%08x\n",
+ result);
if (driver_byte(result) & DRIVER_SENSE)
scsi_print_sense("", cmd);
}
- /*
- * Mark a single buffer as not uptodate. Queue the remainder.
- * We sometimes get this cruft in the event that a medium error
- * isn't properly reported.
- */
- block_bytes = req->hard_cur_sectors << 9;
- if (!block_bytes)
- block_bytes = req->data_len;
- scsi_end_request(cmd, 0, block_bytes, 1);
}
+ scsi_end_request(cmd, 0, this_count, !result);
}
EXPORT_SYMBOL(scsi_io_completion);
@@ -1169,7 +1145,7 @@
* successfully. Since this is a REQ_BLOCK_PC command the
* caller should check the request's errors value
*/
- scsi_io_completion(cmd, cmd->bufflen, 0);
+ scsi_io_completion(cmd, cmd->bufflen);
}
static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd)
